Connections Teaching Toolkit

Perry S. Green, Ph.D. Thomas Sputo, Ph.D., P.E. Patrick Veltri

A Teaching Guide for Structural Steel Connections

PREFACE

This connection design tool kit for students is based on the original steel sculpture designed by Duane S. Ellifritt, P.E., Ph.D., Professor Emeritus of Civil Engineering at the University of Florida. The tool kit includes this teaching guide, a 3D CAD file of the steel sculpture, and a shear connection calculator tool. The teaching guide contains drawings and photographs of each connection depicted on the steel sculpture, the CAD file is a 3D AutoCAD® model of the steel sculpture with complete dimensions and details, and the calculator tool is a series of MathCAD® worksheets that enables the user to perform a comprehensive check of all required limit states. The tool kit is intended as a supplement to, not a replacement for, the information and data presented in the American Institute of Steel Construction’s Manual of Steel Construction, Load & Resistance Factor Design, Third Edition, hereafter, referred to as the AISC Manual. The goal of the tool kit is to assist students and educators in both learning and teaching basic structural steel connection design by visualization tools and software application. All information and data presented in any and all parts of the teaching tool kit are for educational purposes only. Although the steel sculpture depicts numerous connections, it is by no means all-inclusive. There are many ways to connect structural steel members together. In teaching engineering students in an introductory course in steel design, often the topic of connections is put off until the end of the course if covered at all. Then with the crush of all the other pressures leading up to the end of the semester, even these few weeks get squeezed until connections are lucky to be addressed for two or three lectures. One reason for slighting connections in beginning steel design, other than time constraints, is that they are sometimes viewed as a “detailing problem” best left to the fabricator. Or, the mistaken view is taken that connections get standardized, especially shear connections, so there is little creativity needed in their design and engineers view it as a poor use of their time. The AISC Manual has tables and detailing information on many standard types of connections, so the process is simplified to selecting a tabulated connection that will carry the design load. Many times, the engineer will simply indicate the load to be transmitted on the design drawings and the fabricator will select an appropriate connection. Yet connections are the glue that holds the structure together and, standardized and routine as many of them may seem, it is very important for a structural engineer to understand their behavior and design. Historically, most major structural failures have been due to some kind of connection

failure. Connections are always designed as planar, twodimensional elements, even though they have definite threedimensional behavior. Students who have never been around construction sites to see steel being erected have a difficult time visualizing this three-dimensional character. Try explaining to a student the behavior of a shop-welded, field-bolted double-angle shear connection, where the outstanding legs are made purposely to flex under load and approximate a true pinned connection. Textbooks generally show orthogonal views of such connections, but still many students have trouble in “seeing” the real connection. In the summer of 1985, after seeing the inability of many students to visualize even simple connections, Dr. Ellifritt began to search for a way to make connections more real for them. Field trips were one alternative, but the availability of these is intermittent and with all the problems of liability, some construction managers are not too anxious to have a group of students around the jobsite. Thought was given to building some scale models of connections and bringing them into the classroom, but these would be heavy to move around and one would have the additional problem storing them all when they were not in use. The eventual solution was to create a steel sculpture that would be an attractive addition to the public art already on campus, something that would symbolize engineering in general, and that could also function as a teaching aid. It was completed and erected in October 1986, and is used every semester to show students real connections and real steel members in full scale. Since that time, many other universities have requested a copy of the plans from the University of Florida and have built similar structures on their campuses.

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INTRODUCTION

Connection design in an introductory steel course is often difficult to effectively communicate. Time constraints and priority of certain other topics over connection design also tend to inhibit sufficient treatment of connection design. The Steel Connections Teaching tool kit is an attempt to effectively incorporate the fundamentals of steel connection design into a first course in steel design. The tool kit addresses three broad issues that arise when teaching students steel connection design: visualization, load paths, and limit states. In structural analysis classes, students are shown idealized structures. Simple lines represent beams and columns, while pins, hinges, and fixed supports characterize connections. However, real structures are composed of beams, girders, and columns, all joined together through bolting or welding of plates and angles. It is no wonder that students have trouble visualizing and understanding the true threedimensional nature of connections! The steel sculpture provides a convenient means by which full-scale steel connections may be shown to students. The steel sculpture exhibits over 20 different connections commonly used in steel construction today. It is an exceptional teaching instrument to illustrate structural steel connections. The steel sculpture’s merit is nationally recognized as more than 90 university campuses now have a steel sculpture modeled after Dr. Ellifritt’s original design. In addition to the steel sculpture, this booklet provides illustrations, and each connection has a short description associated with it. The steel sculpture and the booklet “show” steel connections, but both are qualitative in nature. The steel sculpture’s connections are simply illustrative examples. The connections on the steel sculpture were not designed to satisfy any particular strength or serviceability limit state of the AISC Specification. Also, the narratives in the guide give only cursory descriptions, with limited practical engineering information. The main goals of this Guide are to address the issues of visualization, load paths, and limit states associated with steel connections. The guide is intended to be a teaching tool and supplement the AISC Manual of Steel Construction LRFD 3rd Edition. It is intended to demonstrate to the student the intricacies of analysis and design for steel connections. Chapters in this guide are arranged based on the types of connections. Each connection is described discussing various issues and concerns regarding the design, erectability, and performance of the specific connection. Furthermore,

every connection that is illustrated by the steel sculpture has multiple photos and a data figure. The data figure has tables of information and CAD-based illustrations and views. Each figure has two tables, the first table lists the applicable limit states for the particular connection, and the second table provides a list of notes that are informative statements or address issues about the connection. The views typically include a large isometric view that highlights the particular location of the connection relative to the steel sculpture as well as a few orthogonal elevations of the connection itself. In addition to the simple views of the connections provided in the figures, also included are fully detailed and dimensioned drawings. These views were produced from the full 3D CAD model developed from the original, manually drafted shop drawings of the steel sculpture. The guide covers the most common types of steel connections used in practice, however more emphasis has been placed on shear connections. There are more shear connections on the steel sculpture than all other types combined. In addition to the shear connection descriptions, drawings, and photos, MathCAD® worksheets are used to present some design and analysis examples of the shear connections found on the steel sculpture. The illustrations, photos, and particularly the detail drawings that are in the teaching guide tend to aid visualization by students. However, the 3D CAD model is the primary means by which the student can learn to properly visualize connections. The 3D model has been developed in the commonly used AutoCAD “dwg” format. The model can be loaded in AutoCAD or any Autodesk or other compatible 3D visualization application. The student can rotate, pan and zoom to a view of preference. The issue of limit states and load paths as they apply to steel connections is addressed by the illustrations and narrative text in the guide. To facilitate a more inclusive understanding of shear connections, a series of MathCAD® worksheets has been developed to perform complete analysis for six different types of shear connections. As an analysis application, the worksheets require load and the connection properties as input. Returned as output are two tables. The first table lists potential limit states and returns either the strength of the connection based on a particular limit state or “NA” denoting the limit state is not applicable to that connection type. The second table lists connection specific and general design checks and returns the condition “OK” meaning a satisfactory value, “NA” meaning the check is not applicable to that connection type, or a phrase describing the reason for an unsatisfactory check (e.g.

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“Beam web encroaches fillet of tee”). The student is encouraged to explore the programming inside these worksheets. Without such exploration, the worksheets represent “black boxes.” The programming must be explored and understood for the benefits of these worksheets to be realized. A complete user’s guide for these worksheets can be found in Appendix A. Contained in the guide is one example for each type of shear connection illustrated by the steel sculpture. Each example presents a simple design problem and provides a demonstration of the use of the worksheet. Appendix B provides a list of references that includes manuals and specifications, textbooks, and AISC engineering journal papers for students interested in further information regarding structural steel connections.

columns. Thus. the steel sculpture is a tree-like structure in both the physical and hierarchical sense. The simply supported girder-to-column connections on the upper shaft are all propped cantilevers of some form. The enclosed CD contains 18 CAD drawings of the steel connections sculpture which may serve as a useful graphical teaching aid. the steel sculpture consists of 25 steel members.
*
The identification/labeling scheme for beams. the steel sculpture does indeed resemble a tree “branching” out to lighter and shorter members. The east-end upper girder. East. the arrangement of members and connections on the steel sculpture may seem complex and unorganized. the third character is either an “A” or “B” identifying that the beam frames into either the “A” or “B” side of the girder. A major connection is made to each face of the upper and lower shafts. At first glance. The first character is a “C” and the second character is a number. over 26 weld groups. Like girders. 43 connection elements. The channel shaped brace (Beam B5A) spans diagonally across two girders (Girder B5 and Girder B8). A bill of material is included for each layout drawing. There are four complete elevations of the sculpture followed by thirteen layout drawings showing each connection on the sculpture.CHAPTER 1 The Steel Sculpture
As a structure. A tension rod and clevis support the upper west girder (Girder B6). The drawings are based on a 3D model of the sculpture. (Girder B8)* is supported by the pipe column that acts as a compression strut. Seven of the eight faces have a girder-to-column connection while the eighth face supports a truss (partial). The first character is a “B” and the second character is a number. This channel is supported by the south girder (Girder B5) and also provides support for the east girder (Girder B8). from the base. and more than 144 individual bolts. lighter section is a W12×106 and the lower. • • Plates have two character labels that are both are lower-case letters. Each member and component is fully detailed and dimensioned. photos. Both shafts are W12-series cross-sections. The upper. The first character is an “a”. The first character is a “p”. roughly 13 ft tall is comprised of two shafts spliced together 7 ft -6in. In general terms. and illustrations best describe the position of the members and connections on the steel sculpture on subsequent pages. the first character is a “B” and the second character is a number. or West). South. upon closer inspection it becomes apparent that the position of the members and connections were methodically designed to illustrate several specific framing and connection issues. the steel sculpture is an innovative aesthetic composition of multiform steel members. united by an assortment of steel elements demonstrating popular attachment methods. The drawings. Girders have two character labels. As a piece of art. transferring load to the lower girder (Girder B4). Two short beams frame to the web of each girder near their cantilevered end. Angles have two character labels that are both lowercase letters. Since two beams frame into the web of each girder.
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. heavier section is a W12×170. Each shaft of the column has four faces (two flanges and two sides of the web) and each face is labeled according to its orientation (North. and girders with respect to the drawings included in this document is as follows: • • • Columns have two character labels. A central column. Beams have three character labels. However. The upper shaft girder-to-column connections and all of the beam-to-girder connections are simple shear connections.

The controlling strength limit state is the specific condition that has the lowest resistance to the given design load. Design loads and design strengths are obtained when the service loads and nominal resistance values are multiplied by the appropriate load and resistance factors. strength-based limit states for connections can be based on either the material (members) or the fasteners. Strength relates to safety and is essentially the capacity of a structure or member to carry a service or ultimate design load. Stiffness is typically associated with serviceability. Leon. Serviceability is concerned with various performance criteria of a structure or member during service loading and unloading. through or along the element or member. and resistance factors (also known as φ factors) reduce the nominal resistance of a member. The inverse design procedure is also acceptable: design for serviceability and then check strength. or flexural forces. a limit state has been reached. However. Block shear can
Figure 2-1.A. A limit state is the condition where the structure or member is functionally inadequate. most designers tend to proportion elements based on strength requirements then check that the particular design meets applicable serviceability limit states. Thus. This limit state is so named because the associated failure path tears out a “block” of material. A single connection might include a large number of structural members and several fastener groups. refining if necessary.CHAPTER 2 Limit States
Structural design is based on the concept that all structural members are designed for an appropriate level of strength and stiffness. some based on strength and others based on serviceability. Serviceability limit states typically involve providing an appropriate amount of stiffness or ductility in a structural element. The controlling limit state can be either strength related or based on serviceability criteria. Each strength limit state has a particular failure path across. Structural elements tend to have several limit states. an appropriate stiffness level must be provided to satisfy applicable serviceability requirements. Regardless of the methodology the controlling limit state dictates the optimal design. shear. For acceptable safety and satisfactory performance of the structure. The following pages have descriptions and figures that explain the general applicability of the more common connection limit states. Structural members must be proportioned with sufficient design strength to resist the applicable design loads. The resistance factors account for the possibility of lower than anticipate strength. the basic components of connections are the fastening system and the attached plies of material. Connection strength limit states of both the fasteners and the plies of material result from tension. The failure path is the line along which the material yields or ruptures. BSR BLOCK SHEAR RUPTURE
Block shear rupture is a limit state in which the failure path includes an area subject to shear and an area subject to tension. The load factors account for the possibility of higher than anticipated loads during service. Load factors increase the nominal loads. In addition to strength. Initially. The applicability of any given limit state is dependent upon the specific connection geometry and loading. the load and resistance factor design philosophy uses statistically based load and resistance factors to modify nominal resistance and service loads. A connection may have many or only a few limit states. When loads exceed the design strength or serviceability requirements. courtesy of Georgia Institute of Technology)
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. Block Shear Rupture Limit State (Photo by J. Swanson and R. These figures are only a guide and are not meant to represent any and all possible combinations of limit states. The serviceability requirements depend on the intended function of the member or element under consideration.

The only difference between the treatments of either the bolted or welded block shear limit state is that in the absence of bolt holes. Bolts that fail in tension will do so within the threaded portion of the bolt. The AISC specification contains two design equations. Bolt Tension Fracture Limit State (Photo by J. The shear strength of a bolt is directly proportional to the number of interfaces (shear planes) between the plies within the grip of the bolt that a single shear force is transmitted through. Eccentrically loaded bolt groups are subject to a moment force that induces either additional shear (for in-plane loads) or combined shear and tension (for out-of-plane loads).A.A. Leon. requires an individual shear force vector evenly distributed across the plies. triple shear. Figure 2-1 shows the condition of the gusset plate well after the block shear rupture limit state has occurred. double-sided connections) If the load path does not pass through the center of gravity of a bolt group. however some of these eccentricities are small and are commonly neglected. then the load is considered eccentric.g. BS BOLT SHEAR
condition where there are indeed two or more shear planes. In reality most connections possess some degree of eccentricity. Leon. Single shear occurs when the individual shear force is transmitted through bolts that have two plies within the grip of the bolt. BB BOLT BEARING
Bolt bearing is concerned with the deformation of material at the loaded edge of the bolt holes. There may be a
Figure 2-3. Bearing capacity of the connection is influenced by the proximity of the bolt to the loaded edge. (e. Three plies of material represent two shear planes. Bolt Shear Limit State (Photo by P. BT BOLT TENSION FRACTURE
If bolts are subject to loading along their length then the bolt is loaded in tension. etc. the gross areas are equal to the net areas. Bolt Bearing Limit State (Photo by J. courtesy of Georgia Institute of Technology)
Figure 2-4. Additional plies further distribute the shear force. Swanson and R. thus the bolt or bolt group is in double shear and has effectively twice the strength as single shear.S. Green)
BS
Figure 2-2. It is important to realize that double shear. but the forces are not evenly distributed. courtesy of Georgia Institute of Technology)
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. through one of the
Bolt shear is applicable to each bolted ply of a connection that is subjected to shear. one equation is based on strength (when deformation around bolt holes is not a consideration) and the other is based on serviceability (when deformation around the bolt holes is a design consideration).occur in plies that are bolted or in plies that are welded. Swanson and R. Bolt bearing is applicable to each bolted ply of a connection.

. Web Local Buckling Limit State (SAC Project)
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. Murray. 1964)
Figure 2-7. This bearing area creates a concentrated reaction at the end of the beam. The applicable limit states depend on the specific connection geometry. Christopher. the flanges of the supported member transfer concentrated tension and
Figure 2-6. Since most moment connections provide continuity between the supporting and supported members. The limit states for concentrated forces most often occur in seated connections and moment connections. The web of the supported beam is susceptible to web crippling and web local yielding.S. CONCENTRATED FORCES FLB FLANGE LOCAL BENDING WEB COMPRESSION BUCKLING
WCB
WC
WEB CRIPPLING WEB LOCAL BUCKLING
WLB
WLY WEB LOCAL YIELDING Sometimes forces that are transferred from one member to another create localized deformation (yielding) or buckling. Flange Local Bending Limit State (Beedle. flange material has been removed) the remaining web may be susceptible to web local buckling.e. the outstanding angle leg on the seat provides a bearing area for the bottom flange of the supported beam. For example. when the supported beam is coped. For seated connections. This coincides with the least cross-sectional area. Web Crippling Limit State (Photo by T.roots of the threads. Virginia Tech)
Figure 2-5. R.. L. (i.

Prying action is a phenomenon in which additional tension forces are induced in the bolts due to deformation of the connection near the bolt. Other instances of flexural yielding are flexure of the stem of a tee shape in a shear tee connection and bending of the outstanding angle leg of an unstiffened seated connection. shear yielding will usually control over shear rupture.. For welded plies. without bolt holes. web crippling and web compression buckling limit states must be investigated. Flexibility of the connected parts within the grip of the bolts creates these additional tension forces. et al. Flange local bending. PA PRYING ACTION
Most connections are subjected to the shear component of loading.compression forces to the supporting member.. those elements in the connection that are subject to shear forces must be investigated for shear yielding and shear rupture. Both limit states will apply regardless of fastening method (bolt or weld).2.H. Thus. Even moment connections must have provisions for shear transfer. Nader. W. then shear rupture will generally control). web local yielding. the reduced section modulus of the remaining beam cross section may significantly reduce the flexural strength of the member..
Figure 2-9 Tee Stem Deformation (Astaneh. 1997)
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. FY FLEXURAL YIELDING
SY
SHEAR YIELDING AND SHEAR RUPTURE
SR
When a beam is coped. (The net area of welded plies without bolt holes is equal to the gross area. A. If the ratio of yield strength to ultimate tensile strength is less than 1. 1989)
Figure 2-8 Web Local Yielding Limit State (SAC Project)
Figure 2-10 Seat Angle Deformation (Yang.N. M.

Shear Yielding Limit State (Astaneh.N. and Nader. then a potential shear failure path on the beam is present and shear yielding and shear rupture must be investigated for this member. M. 1989)
Figure 2-11.Shear yielding is a ductile limit state.N. it is a function of the net shear area of the element. A. The fastening (bolting or welding) is generally
Figure 2-12. Shear lag often occurs in angle members when they are used as struts. The tension rupture mode is a limit state that is a function of the effective net area.
TY
TENSION YIELDING AND TENSION RUPTURE
TR
The tension yielding limit state is a function of the gross cross-sectional area of the member subjected to tension load. Prying Action Limit State (Photo by J. This net area is further reduced to account for the effects of shear lag. in the direction of load from the top edge of the element to the bottom edge and through the thickness of the ply. If both flanges of the supported member are coped. 1989)
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. it is a function of the gross shear area of the element. and Nader. Leon. Swanson and R. Shear rupture is an ultimate limit state. A. The failure path associated with shear yielding is linear in the direction of load from the top edge of the element to the bottom edge and through the thickness of the ply. Shear lag occurs when the tension force is not evenly distributed through the cross sectional area of a member. The failure path associated with shear rupture is also linear. M. The net area is the reduced gross area due to bolt holes or notches. courtesy of Georgia Institute of Technology)
Figure 2-13.. Shear Rupture Limit State (Astaneh.A. Certain geometric areas of a section may have higher localized stresses.

N. and the effective length is assumed as the base dimension of this trapezoid. The projection is assumed to originate at either the first row of bolts on the plate or the origin of the weld. Weld Shear Limit State (Astaneh. The stress distribution through the ends of members that are attached to the gusset is complex.A. The Whitmore method of analysis assumes the member force is uniformly distributed over an effective area. This unbalance causes a shear force to lag across the section. The projection is assumed to terminate at the plane that passes through the last row of bolts or at the end of the welds. then the load is considered eccentric. This effective area is determined by multiplying the gusset plate thickness by an effective length that is defined from the projection of 30degree lines on each side of the “strut” member that is connected to the gusset plate.made along only one leg of the angle. W WELD SHEAR
Weld shear is applicable to each welded ply of a connection. if the load path does not pass through the center of gravity of a weld group. and Nader. In a similar fashion as bolt shear. courtesy of Georgia Institute of Technology)
Whitmore section yielding or buckling is a limit state that applies to bolted and welded gusset plates and similar fittings that are much wider than the pattern of bolts or welds within them.. 1989)
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. When the angle is loaded in tension the leg that is fastened has a disproportionate share of the tension load. Tension Fracture Limit State (Photo by J. Leon. A. The failure mode for fillet welds is always assumed to be a shear failure on the effective throat of the weld. This limit state involves either the yielding or buckling of plate material near the ends of the attached members. Swanson and R. M. The 30-degree projection lines form a trapezoid. Eccentrically loaded weld groups are subject to a moment that tends to induce either additional shear (for in-plane loads) or combined shear and tension (for out-of-plane loads). WS WHITMORE SECTION YIELDING / BUCKLING
Figure 2-14.
Figure 2-15.

He or she needs to be trained to make the varying degrees of surface preparation required depending on the type of weld specified. This assumes that the shank of the bolt provides load transfer from one ply to the next through direct contact. short-slotted. When bolts are installed in a snug-tightened condition the joint is said to be in bearing as the plies of joined material bear directly on the bolts. diameters in 1/8 in. however the labor associated with welding requires a greater level of skill than installing the bolts. The use of either bolting or welding has certain advantages and disadvantages. and many other variables. Welding requires a highly skilled tradesman who is trained and qualified to make the particular welds called for in a given connection configuration.CHAPTER 3 Joining Steel Members
In current construction practice. Coatings such as paint and galvanizing tend to reduce the mean slip coefficient. steel members are joined by either bolting or welding. the position that is needed to properly make the weld. The reliance on friction between the plies for load transfer means that the surface condition of the parts has an impact on the initial strength of slip-critical connections. Bolting requires either the punching or drilling of holes in all the plies of material that are to be joined. while A490 bolts have a 150 ksi minimum tensile strength. The strength of slip-critical connections is directly proportional to the mean slip coefficient. the welded side will usually be the shop connection and the bolted connection will be the field connection. the bolts act like clamps holding the plies of material together. (Kulak. However. STRUCTURAL BOLTING Structural bolting was the logical engineering evolution from riveting. Riveting became obsolete as the cost of installed high-strength structural bolts became competitive with the cost associated with the four or five skilled tradesmen needed for a riveting crew. Welding that may be required on a connection is preferably performed in the more-easily controlled environment of the fabrication shop. Allowing threads to be included in the shear planes results in a shear strength about 25% less than if the threads are specified as excluded from the shear plane(s). The use of A307 bolts is no longer that common except for the ½-in. the preheat temperature of the parts (if necessary). The initial load transfer is achieved by friction between the faying or contact surfaces of the plies of material being joined. published by the Research Council on Structural Connections (RCSC. The clamping force is due to the pretension in the bolts created by properly tightening of the nuts on the bolts. It is not unusual to have one ply of material prepared with a standard hole while another ply of the connection is prepared with a slotted hole. due to the clamping force of the bolts being normal to the direction of the load. but are not permitted to be galvanized due to hydrogen embrittlement concerns. This practice is common in buildings having all bolted connections since it allows for easier and faster erection of the structural framing. This helps simplify shipping and makes erection faster. A307 bolts have a 60 ksi minimum tensile strength. the load transfer is still in bearing like for snug-tightened joints. increments. oversized. 2000) has been incorporated by reference into the AISC Load and Resistance Factor Design Specification for Structural Steel Buildings. Fisher and Struik. A325 bolts have a 120 ksi minimum tensile strength and are permitted to be galvanized. When fabricating steel for erection. A325 and A490 bolts are designated high-strength bolts. or long-slotted depending on the type of connection.to 1½-in. the material thickness of the parts to be joined. However.
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. The Specification for Structural Joints Using ASTM A325 or A490 Bolts. increments and can be ordered in lengths from 1½ to 8 inches in ¼ in. Welding will eliminate the need for punching or drilling the plies of material that will make up the connection. For slip-critical joints. Bearing connections can be specified with either the threads included (N) or excluded (X) from the shear plane. diameter size where they are still sometimes used in connections not requiring a pretensioned installation or for low levels of load. most connections have the connecting material attached to one member in the fabrication shop and the other member(s) attached in the field during erection. If a connection is bolted on one side and welded on the other. appropriate care must be taken to specify bolt lengths such that the threads are excluded in the asbuilt condition if the bolts are indeed specified as threads excluded. The two most common grades of bolts available for structural steel connections are designated ASTM A325 and ASTM A490. the bolts are pretensioned and the faying surfaces are prepared to achieve a minimum slip resistance. High strength bolts can be either snug tightened or pretensioned. 1987). High strength bolts are available in sizes from ½. These holes may be a standard size. In pretensioned connections. Many of the bolting standards are based on work reported by in the Guide to Design Criteria for Bolted and Riveted Joints.

Bolt. A torque wrench is calibrated to stall at the required tension for the bolt. Guidelines for welded construction are published by the American Welding Society (AWS) in AWS D1. when compared to bolting. Currently. Nut and Washer
Figure 3-3. Twist-off bolts have a splined end that twists off when the torque corresponding to the proper pretension is achieved. Structural Fastener . GMAW and FCAW can be deposited in all positions and have a relatively fast deposit rate compared to other processes. Structural Fastener . twist off bolt. The main difference between the processes is in the method of weld shielding. The most common weld processes are Shielded Metal Arc Welding (SMAW). GMAW and FCAW are similar weld processes that use a wire electrode that is fed by a coil to a gun-shaped electrode holder. then subsequently turning the nut a specific amount based on the size and grade of the bolt to develop the required pretension. GMAW uses an externally supplied gas mixture while FCAW has a hollow electrode with flux material in the core that generates a gas shield or a flux shield when the weld is made. Furthermore. Direct Tension Indicators and Feeler Gages
Figure 3-1. The calibrated wrench method involves using a torque applied to the bolt to obtain the required level pretension. welding should be preferably performed on bare metal.
Figure 3-2. Welding can often simplify an otherwise complicated joint.Twist-off Bolt
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. The amount of compression must then be checked with a feeler gage. However. Flux Core Arc Welding (FCAW). calibrated wrench. Gas Metal Arc Welding (GMAW). The turn-of-the-nut method involves first tightening the nut to the snug tight condition. four installation methods are available: turn-of-the-nut.1 Structural Welding Code-Steel. the divots compress to a certain level. These provisions have been adopted by the AISC in the Load and Resistance Factor Design Specification for Structural Steel Buildings. and Submerged Arc Welding (SAW). Direct tension indicators (DTIs) are special washers with raised divots on one face. SMAW uses an electrode coated with a material that vaporizes and shields the weld metal to prevent oxidation. When the bolt is installed. and direct tension indicator methods. Paint and galvanizing should be absent from the area on the metal that is to be welded. WELDING Welding is the process of fusing multiple pieces of metal together by heating the metal to a liquid state. there is no ASTM specification equivalent for A490 tension control bolts. The selection of a process is due largely to suitability and economic issues rather than strength. ASTM F1852 is the equivalent specification for A325 “twist-off” bolts. The coated electrode is consumable and can be deposited in any position. SMAW is commonly referred to as stick welding.
Several welding processes are available for joining structural steel. welds are subject to size and length limitations depending on the thickness of the materials and the geometry of the pieces being joined.When a pretensioned installation is required.

Fillet weld strength is directly proportional to its length and throat dimension. as in a butt joint. fillet welds are economical. no material overlap). The metal pieces being joined must be prepared by shaping the edges.e. It is more economical to use smaller and longer fillet welds with small legs rather than shorter fillet welds with large legs. the effective throat is permitted to be equal to the weld throat size if the weld is less than 3/8 in. The flux protects and enhances the resulting weld. Fillet and groove welds make up the majority of all structural welds. it is important to realize that the effective throat dimension for the SAW process is calculated differently than for the other processes. the tabulated strength must be reduced by the ratio of thickness provided to minimum thickness or by electrode used to E70 electrode strength (70 ksi). The major limitation of this process is that weld can only be deposited in the flat position due to the granular flux used. For engineers. Fillet welds are by far the most common type of weld used in welded construction. easy to fabricate. The volume of weld material. Finally. corner. vertical. plug. Groove welds that extend through the full thickness of the materials being joined are called complete-joint-penetration groove welds. Joint types are either lap or tee. respectively. or edge. SAW tends to produce high quality welds that are strong and ductile. and require very simple preparation of the materials being joined. corner. There are four types of welds: fillet. is the most expensive part of a structure. shear is always the controlling limit state. In general. Groove welds. lap. a consumable electrode is submerged below a blanket of granular flux. Groove welds are typically used when the plies are aligned parallel and lie in the same plane (i. Regardless of the process or type of welds.
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. and slot. If the structure is loaded cyclically. is proportional to the square of the weld leg. by weight.707 × leg length). Whenever possible. There is an additional economic advantage if the weld can be made in one pass. The welds can be placed in any of four positions depending on the configuration and location of the joint: flat. Additional metal is often used in the form of backing or extension bars and runoff tabs to help contain the weld metal. These are called butt. or edge joint. This obviously adds significant labor costs to the already expensive weld.In SAW welding. Weld strength is based on either the shear strength of the weld or shear strength of the base metal. or to make a tee. These tabulated strength values assume E70 electrodes and have an associated minimum thickness based on shear strength of the weld matching the shear strength of the base metal. Multiple passes require more time and more weld metal. Since the SAW process produces higher quality welds with deeper penetration. the backing bars and runoff tabs must be removed and the surfaces finished smooth. it is beneficial to make a weld in either the horizontal or flat position for ease of workmanship and cost. therefore only those types will be discussed here. horizontal. through the thickness. For the other processes the effective throat is taken as the minimum distance from the root to the face of the weld (for equal legs: 0. The SAW process is most often found automated in the better-controlled conditions of shop welding operations. This process is frequently used for the web-to-flange connections of plate girders. they are called partial-joint-penetration groove welds. Due to labor costs. tee. and overhead. small access holes (known as weld access holes) need to be cut in the web just below and above the top and bottom flanges respectively to allow access to make the weld (bottom) and to allow placement of the backing bar (top). The largest
weld size that can be deposited in one pass in the horizontal or flat position is normally 5/16 in. In the AISC Manual. when groove welds are used for beam flange connections. the shear connections have tables for standard elements and weld lengths. There are five types of structural joints that can be made using either fillet or groove welds. weld metal. are potentially expensive. Weld material strength should be matched to the base metal so that the resulting weld is stronger than the pieces of metal being joined.11 in. If less than the minimum material thickness is present or the weld is not made with an E70 electrode. and therefore the cost. When the welds do not extend completely through the thickness. groove. For larger welds the effective throat for SAW welds is the minimum distance from the root to face of the weld plus 0. particularly complete-joint-penetration groove welds.

.

The tables have limited effectiveness for analysis or design of connections with unusual geometry. angle. Many shear connection elements can be either bolted on the supported side and welded on the supporting side. SHEAR CONNECTION EXAMPLES & MATHCAD® WORKSHEETS Shear connections are the workhorse of structural steel framing. there are a few points that must be noted concerning the use of the design tables. The attachment of a shear connection may be made to the web of the supported beam. ignoring this resistance produces a conservative result. A36) to provide rotational flexibility in excess of what the supported member requires. Second. The majority of the rotational flexibility of most shear connections is achieved in the deformation of the connection element (plate. material strength. MathCAD® worksheets were developed for six types of shear connections: Double-Angle. if it is a welded connection usually adds little to the overall connection flexibility. For design purposes. all-welded shear connections are usually impractical. shear connections exhibit relatively complex behavior and tend to have a significant number of limit states that need to be checked. refer to the MathCAD® User’s Guide. the majority of structural steel building connections are shear connections. Individually. tee. if it is a bolted connection. Experimentally it has been shown that shear connections possess some amount of rotational restraint. and most significant. For these reasons.) affects the strength and/or controlling limit state.e. Even most moment connections integrate a shear connection to carry the shear component of the beam reaction. The tables provide little information as to which limit state controls the design. many shear connections are bolted on one side (to either the supported member or the supporting member) and welded on the other. Although the tables provide a quick and simple way to design shear connections. A rigid support is typically connected to the center of a column flange on the supporting side (if the support is rigid rotation occurs largely in the connection element). The stiffness and strength of some connections depend on whether or not the supported member is considered “flexible” or “rigid”. Shear End-Plate. Single Plate. other applicable limit states may need to be checked. For instructions and information regarding the MathCAD® software application. or welded on the supported side and bolted on the supporting side. bolt size. The deformation of the fasteners. These are qualitative definitions and it is up to the discretion of the engineer as to whether the support should be treated as flexible or rigid. no moment forces are assumed transmitted by the connection from the supported member to the supporting member.) or through slotted or oversized holes.
Connections Teaching Toolkit • 4-1
. SingleAngle and Shear Tee. or all-bolted or all-welded. or the welds. The exception is the seated connection where the connection is made to the flanges of the supported beam. from an erectability point of view. The worksheets allow the user to see how a change in any particular connection parameter (i. Shear connection elements are typically designed using thin and/or mild yield strength materials (i. However.CHAPTER 4 Simple Shear Connections
Simple shear connections are assumed to have little or no rotational resistance. Since it is a common practice to weld shop attachments and bolt field attachments. The AISC Manual has tables that list design strengths for most shear connections. etc. a flexible support is one in which the supporting side of the element is attached to either a girder or column web where deformation of the web contributes to rotational flexibility (if the support is flexible rotation occurs largely in the supporting member). the pin is assumed to be located at the most flexible part of the connection. element thickness. When designing shear connections. usually with the flanges unconnected. Therefore. Unstiffened Seat. etc. The goal for shear connections is to have both adequate strength and sufficient rotational ductility. The first is that the tables list strengths based on assumptions of standardized connection geometry. For specific instructions and information regarding the use and installation of the MathCAD® worksheets see Appendix A. These worksheets are included on the companion CD that came with this guide. The terms “flexible” and “rigid” as they refer to the supporting side of a connection are subjective and somewhat open to interpretation. They are assumed to carry only the shear component of the load and are idealized as pins or rollers for design. In general. Additionally. is that the tables list only the controlling strength of the connection. Today.e. This prevents any sort of comparison of the applicable limit states for the connection.

These double-angles are field bolted to the supporting girder and shop bolted to the supported beam. The offset bolt rows between the in-plane and outstanding angle legs provide better entering and tightening clearances.Figure 4-1 Shear Connection: All-Bolted Double-Angle
Girder B1 / Beam B1B
Limit States
Block Shear Rupture Bolt Bearing Bolt Shear Flexural Yielding Local Web Buckling Shear Rupture Shear Yielding
N
West Elevation
South Elevation
Notes
• • Girder B1 supports Beam B1B by an all-bolted. the beam is double coped to accommodate the flanges of the girder. This eliminates "knifed" erection.
• •
4-2 • Connections Teaching Toolkit
. Since both of the members are the same depth. double-angle connection. (Lowering the supported beam web into place between the angles).

Fu = 58 ksi). in order to establish a rational and comprehensive set of shear connection examples. Therefore. Shear Connection: All-bolted double-angle Girder B1 / Beam B1B
Figure 4-3. To perform the analysis. as larger welds provide no strength advantage once the limiting thickness has been reached. or flange or web of the supporting column. • The MathCAD® worksheets will only accept valid AISC W-shapes as supporting and supported members. Often the strength based on bolt shear alone is the same on either ply of the doubleangle. typically there are two lines of bolts on the supporting side (one bolt line on each outstanding leg) and one line of bolts on the supported side. bearing connections in standard holes. W-shapes with section properties similar to those of S-shapes or channels will be substituted. Fu = 65 ksi).
Figure 4-2. The same general idea is also applicable for allwelded double-angle connections. The number of bolt rows is usually common to both sides.
Standard all-bolted or all-welded double-angle connections are efficient from a material standpoint. several basic assumptions are made: • All wide-flange members are ASTM A992 steel (Fy = 50 ksi. The two bolt lines on the supporting side are in single shear and the one bolt line one the supported side is in double shear. Although the supported side may have half as many bolts. Shear Connection: All-bolted double angle Girder B1 / Beam B1B
Connections Teaching Toolkit • 4-3
. For an allbolted double-angle connection. To facilitate erection the connection may have short slotted holes and/or a detailed length such that the overall member length is slightly shorter than the span with shims provided to fill any gap. DOUBLE-ANGLE CONNECTION Double-angle connections are made by attaching the inplane pair of legs (by bolting or welding) to the web of the supported beam and the out-of-plane pair of legs (also by bolting or welding) to the web of the supporting beam. If less than the tabulated thickness is provided the tabulated weld values must be reduced by the ratio of thickness provided to thickness required. Welds on the supported side (referred to in the AISC Manual as Weld A) are typically placed along the toe and/or across the top and bottom edges of both in-plane angle legs. If the angles are shop attached to the face of the supporting column.The steel sculpture connections were not designed for any particular loading. • All bolts are ASTM A325-N. A few of the supported beams on the steel sculpture are S-shapes or channels rather than W-shapes. they are in double shear. Welds on the supporting side (referred to in the AISC Manual as Weld B) are typically placed along each toe of the outstanding legs of the angle with a return at the top. Thus. • The design load for the shear connections is equal to one half the maximum design uniformly distributed load (½ UDL) based on the span to depth ratio of the supported member. • All welds are made using E70 electrodes and are produced by the SMAW process. then the supported beam will be erected in a knifed manner where the bottom flange of the supported beam is coped allowing it to be lowered into position between the in-plane angle legs. • The beams and girders have a simple span (with full lateral support) equal to 20 times their nominal depth (rounded up to the next whole foot). Minimum tabulated thickness in the manual for welding assumes E70 electrodes and are based on matching shear rupture strength of the weld with the shear rupture strength of the base metal. • All other shapes and plates are ASTM A36 steel (Fy = 36 ksi. longer yet smaller welds are better suited.

and erection convenience. the holeto-hole gage is generally kept the same.
4-4 • Connections Teaching Toolkit
. as in cantilevered roof framing). The top edges of angles (as well as other shear connectors) on the supporting side should not be welded across the top. This allows erection of the beam with the additional bolt row until the other beam can be fitted up. and B8B are examples of doubleangle connections. The practice of using temporary erection bolts for support of a member to create an all-welded connection tends to nullify the reason for welding. For given angle sizes. The usual gages are a function of the angle leg dimension and are based on design. One solution to the problem is illustrated on the steel sculpture . Other solutions involve providing one additional bolt in two opposite corners of each connection. however.g. Guidance is provided in the AISC Manual for angle thickness and gage requirements to ensure adequate rotating flexibility. Both the outstanding angle legs and the areas they frame into have not been painted. Since both the supporting girder and the supported beam are the same depth (W18 series) and the top flanges of both beams are aligned. B8A. Shop welding has been performed on the supported side of each beam.provide an additional row of bolts on one of the double-angles that is not shared with the other. Temporary erection bolts are usually used to support and stabilize members during erection. When such connections would occur in column webs. Rather. B3B. it is through the deformation of the outstanding legs that the rotational flexibility is achieved. At least one of the members must somehow be supported so that the double-angle can be welded. If the entire top edge of the outstanding angle leg were welded. or offsetting the beams such that they both share only one bolt line. The absolute position and spacing of bolt holes are controlled by either clearance or edge distance limitations. The B3A/B3B joint is an example of a back-to-back condition with two double-angle connection sharing bolts. Field welding should be performed on unpainted bare steel. the supported beam must be double coped to permit erection. On the steel sculpture. B8. Whether bolted or welded. current OSHA safety standards prohibit this unless erectability is provided for with an erection seat or other means. The welds are placed along the toe of each of the outstanding angles. The double-angles have been shop assembled on the supported side. except for short weld returns. connections of members B1B. Note that the bolts common to both connections are not in double shear. thus the entire outstanding angle legs are available for deformation. B3A. The top of the supported beam has been coped to allow the flanges to be aligned vertically. it would inhibit its flexibility and thus the rotational flexibility of the connection. they are in single shear on two planes. or in girder webs directly over the top of a column (e. The B1B connection is an all-bolted double-angle connection with rows of bolts on the supporting member side offset from those on the supported member side. fabrication. common gages have been established by usage. for some regularity. The offset pitch requires the angles to be slightly longer but provides better entering and tightening clearances. Welds on the supporting member side have ductility concerns. All-welded double-angle connections are difficult to erect.
Girder B8 represents an all-welded arrangement of double-angle connections.The assumed location of the idealized pin for a doubleangle connection is at the outstanding legs.

The girder web is shared between two double-angle connections. The double-angles are shop welded to the supported beam and field bolted to the supporting girder. The top flanges of both the beam and the girder are at the same elevation.Figure 4-4 Shear Connection: Bolted-Welded Double-Angle
Girder B3 / Beam B3A
Limit States
Block Shear Rupture Bolt Bearing Bolt Shear Flexural Yielding Local Web Buckling Shear Rupture Shear Yielding Weld Strength
N
East Elevation
North Elevation
Notes
• • • Girder B3 supports Beam B3A by a bolted-welded double-angle connection.
• •
Connections Teaching Toolkit • 4-5
. Welds on the supported side are placed along the toe of each angle and optionally along the top or bottom edges of both angles. The top flange of the supported beam is coped to eliminate the interference of girder flange. The additional row of bolts holds the east side connection temporarily in place until the west side connection can be fitted up.

The double-angles are shop welded to the supported beam and field bolted to the supporting girder.Figure 4-11 Figure 4-9 Shear Connection: Bolted-Welded Double-Angle Shear Connection: Bolted-Welded Double-Angle
Girder B3 Beam B3B Girder B3 / / Beam B3B
Limit States
Block Shear Rupture Bolt Bearing Bolt Shear Flexural Yielding Local Web Buckling Shear Rupture Shear Yielding Weld Strength
N
West Elevation
North Elevation
Notes
• • • Girder B3 supports Beam B3B by a bolted-welded double-angle connection. The top flange of the supported beam is coped to eliminate the interference of girder flange. The top flanges of both the beam and the girder are at the same elevation. The additional row of bolts holds the east side connection temporarily in place until the west side connection can be fitted up. Welds on the supported side are placed along the toe of each angle and optionally along the top or bottom edges of both angles.
• •
Connections Teaching Toolkit • 4-7
. The girder web is shared between two double-angle connections.

The double-angles are field welded to the supporting girder and shop welded to the supported beam. Welds on the supported side are placed along the toe of each angle and optionally along the top or bottom edges of both angles. welding across the entire top edge should be avoided since it would inhibit the flexibility of the connection. oil or grease) Welds on the supporting member should be placed along the toe and optionally along the bottom edge of the angle.
•
4-8 • Connections Teaching Toolkit
. the area of attachment must be free of any coatings (i.e. paint) or lubricants (i.e.Figure 4-12 Shear Connection: All-Welded Double-Angle
Girder B6 / Beam B8B
Limit States
Shear Yielding Shear Rupture Weld Strength
N
North Elevation
West Elevation
Notes
• • • • Girder B6 supports Beam B8B by an all-welded double-angle connection. Properly sized weld returns should be provided at the top edge of the angle. When connection elements are field welded to members.

welding across the entire top edge should be avoided since it would inhibit the flexibility of the connection. oil or grease) Welds on the supporting member should be placed along the toe and optionally along the bottom edge of the angle.Figure 4-13 Figure 4-15 Shear Connection: Bolted-Welded Double-Angle Shear Connection: All-Welded Double-Angle
Girder B8 / Beam B8A Girder B8 / Beam B8A
Limit States
Shear Rupture Shear Yielding Weld Strength
N
North Elevation
East Elevation
Notes
• • • • B8 girder supports Beam B8A by an all-welded double-angle connection.e. Welds on the supported side are placed along the toe of each angle and optionally along the top or bottom edges of both angles. When connection elements are field welded to members. the area of attachment must be free of any coatings (i. Properly sized weld returns should be provided at the top edge of the angle. paint) or lubricants (i. The double-angles are field welded to the supporting girder and shop welded to the supported beam.e.
•
Connections Teaching Toolkit • 4-9
.

paint) or lubricants (i. welding across the entire top edge should be avoided since it would inhibit the flexibility of the connection.e. the area of attachment must be free of any coatings (i. When connection elements are field welded to members. Welds on the supported side are placed along the toe of each angle and optionally along the top or bottom edges of both angles.Figure 4-14 Figure 4-18 Shear Connection: Bolted-Welded Double-Angle Shear Connection: All-Welded Double-Angle
Column C2 / Girder B8 Column C2 / Girder B8
Limit States
Shear Rupture Shear Yielding Weld Strength
N
North Elevation
East Elevation
Notes
• • • • Column C2 supports Girder B8 by all-welded double-angles.
•
4-10 • Connections Teaching Toolkit
. The double-angles have been field welded to the supporting column and shop welded to the supported girder. Properly sized weld returns should be provided at the top edge of the angle.e. oil or grease) Welds on the supporting member should be placed along the toe and optionally along the bottom edge of the angle.

S shapes are not commonly used in steel framing today. The vertical dimension of the plate should not exceed that of the supported beam web. the attachment for a seated connection is not made at the web of the supported beam. The seat angle may be attached to the supporting member either by bolting or welding. If less than the tabulated thickness is provided. Thus. gage spacing. In the AISC Manual. provides a “seat” upon which the beam rests and supports the reaction. the assumed location of the idealized pin is at the plate itself. Beam B2A illustrates a shear end-plate connection. Shear Connection: Bolted shear end-plate Girder B2 / Beam B2A
Figure 4-22. A seated connection is made from an angle that is mounted to the support such that one leg is vertical against the face of the supporting member. Shop welding is the only method of joining the supported beam web and the plate. Beam B2A is an American Standard (S) shape. outstanding angle leg. The detailed length is normally established such that a small erection gap is present. In the AISC Manual.SHEAR END-PLATE CONNECTION A shear end-plate connection involves welding a plate perpendicular to the end of the supported web and bolting or welding the plate to the supporting member. and field bolted to the girder. The plate is shop welded to the supported beam web. the minimum tabulated thickness for welding the seated connection assumes E70 electrodes and is based on matching the shear rupture strength of the
Figure 4-21. the horizontal dimension will depend on the bolt size. Shear end-plates are generally simple to design but require good control of tolerances in fabrication since the detailed length must fit between supports. and connection length. the minimum tabulated thickness for welding assumes E70 electrodes and is based on matching shear rupture strength of the weld with the shear rupture strength of the base metal. This gap can be filled with shims. but used here for illustration purposes. The seat angle also provides a location to place the supported beam during erection as the angle is shop attached to the supporting member. characterized by tapered flanges. the tabulated weld values must be reduced by the ratio of thickness provided to thickness required. gage lines. Unlike all the other shear connections. The shear plate essentially has only one ply. longer yet smaller welds are better suited as larger welds provide no strength advantage once the limiting thickness has been reached. The rotation flexibility for a shear plate will approximate that of a double-angle connection with similar thickness. If the supporting side is bolted. and the other. and edge distance. UNSTIFFENED SEATED CONNECTION The unstiffened seated connection is somewhat unique to the family of shear connections. Shear Connection: Bolted shear end-plate Girder B2 / Beam B2A
4-12 • Connections Teaching Toolkit
.

weld with the shear rupture strength of the base metal. If less than the tabulated thickness is provided, the tabulated weld values must be reduced by the ratio of thickness provided to thickness required. Thus, longer yet smaller welds are better suited than shorter larger welds, which provide no strength advantage once the limiting thickness has been reached. Unlike other shear connections, bearing limit states, due to concentrated forces are applicable to seated connections. The bottom flange of the supported beam bears on the outstanding angle leg. Therefore, the additional limit states of web local crippling and web local buckling of the supported member must be investigated. If the supported beam were to be simply placed on the seat angle, it might roll over or slide off under loading. To prevent the beam from sliding off the angle, the bottom flange of the beam must be attached to the outstanding angle leg and this is usually done by bolting with 2 A325 bolts. To prevent the beam from rolling over, an additional stabilizing angle must be attached to the top flange or along the web of the supported beam. AISC has no particular strength requirement associated with the stability angle. It should be noted that these additional attachments provide some additional stiffness to the connection. The AISC Manual of suggests using a 4 × 4 × ¼ angle attached with the minimum size fillet weld or two bolts. However, only the seat angle is assumed to provide strength for the connection. Rotational flexibility of the unstiffened seat connection is achieved through the deformation of the outstanding leg of the seat angle, as well as deformation in the top or side angle. The seat angle must be thick enough to carry the reaction but thin enough to provide rotational flexibility. If the seat angle is welded to the supporting member, the welds should be placed along the vertical edges of the angle. Welds for the supporting and supported side of the stability angle should be placed at each toe of the angle legs. Welding along the vertical edges of a top angle would inhibit the flexibility of the connection. The end of the beam bears on the seat angle; thus web crippling and local web yielding of the supported beam must be checked. Beams B5 and B6 represent unstiffened seat connections. Beam B5 has the vertical seat angle leg bolted to the column flange. The bottom flange of the supported beam is welded to the seat. The top angle is attached to the top flange of the beam. Beam B6, on the other hand, has the vertical seat angle leg welded to the column web. The seat is bolted to the bottom flange of the supported beam. The B6 connection also has the top angle located in the optional side position.

Notes
• • • • • Column C2 supports Girder B5 by a bolted-welded seat connection. The seat angle is field bolted to the supporting column and shop welded to the supported girder. The top angle only provides stability to the supported beam. All shear is assumed to be carried by the seat angle. The attachment of the outstanding angle leg to the bottom flange of the girder is only to prevent the beam from slipping off the seat. The seat provides bearing for the bottom flange of the girder, thus web crippling and local web yielding limit states must also be considered.

Notes
• • • • • Column C2 supports Girder B6 by a welded-bolted seat connection. The seat angle is shop welded to the supporting column and field bolted to the supported girder. The top angle only provides stability to the supported beam. All shear is assumed to be carried by the seat angle. The attachment of the outstanding angle leg to the bottom flange of the girder is only to prevent the beam from slipping off the seat. The seat provides bearing for the bottom flange of the girder, thus web crippling and local web yielding limit states must also be considered.

4-16 • Connections Teaching Toolkit

SINGLE-PLATE (SHEAR TAB) CONNECTION The single-plate (or shear tab) connection consists of a plate welded to the supporting member and bolted to the web of the supported beam. Since this connection is one sided it can be easily erected by swinging the supported beam into position from the side. The equations in the AISC Manual are based on E70 electrodes. The weld size on each side of the plate should be three-quarters the thickness of the single plate to ensure that weld strength is not the controlling element in the connection. The orientation of the single-plate connection is in the plane of the web of the supported member. This means that the rotational flexibility and the idealized location of the pin are dependent on the relative rigidity of the plate and the support (and whether or not short slotted holes are used). If the support is flexible then the rotation is accommodated by the deformation of the supporting member. If the support is rigid, then the rotation occurs primarily within the plate connection. Recommended upper and lower bound plate thickness have been established for this connection type. The lower bound plate thickness is to control local buckling assuming the bottom half of the plate is in compression due to flexure. The minimum thickness is a function of the length of the plate, L, material yield stress, Fy, and a plate buckling coefficient, K. The minimum thickness equals:

Eccentricity must always be considered in the design of single-plate connections. The eccentricity, for calculation purposes, may be one of four possible cases depending on the rigidity of the support and whether standard or short slotted holes are used. The two equations for short slotted holes (rigid and flexible support) are nearly identical. Likewise, the two equations for the standard holes (rigid and flexible support) are also nearly identical. Based on either standard holes or short slotted holes, the only difference in the formula for eccentricity between a rigid support and a flexible support is that the flexible support equations have a lower bound value associated with them. The lower bound value for the flexible support is equal to the horizontal distance from the weld line to the bolt line. The steel sculpture shows a single-plate connection with Beam B2B. The plate is welded to the supporting girder and bolted to the supported beam. Assuming standard holes this would correspond to a flexible support condition. The sup ported beam is top coped to provide vertical alignment of between the top flange of the girder and beam. SINGLE-ANGLE CONNECTION A single-angle connection is similar to a double-angle connection, except that only one angle is used. The outstanding and in-plane legs of the single-angle can be attached to either the supporting or supported member by bolting or welding. In a fashion similar to the single-plate connection, the single-angle connection is a one-sided connection, allowing the supported beam to be swung, rather than lowered, into place. Single-angles are normally shop attached to the supporting member. When field bolting, short slots in the angle can provide any needed adjustment. Single-angle connections are simple to erect particularly when shop attached to the support. A standard all-bolted, single-angle connection has all the bolts in single shear.

L 234

Fy K

but not less than ¼ in. The upper bound thickness is to ensure adequate rotational ductility in the plate. The maximum plate thickness is a function of the bolt diameter used, db, and is equal to db/2 + 1/16 in. but not less than the minimum plate thickness previously established.

Only A36 grade steel should be used for single-plate connections. This is a one sided connection. The top flanges of both the beam and the girder are at the same elevation.Figure 4-30 Shear Connection: Single-Plate
Girder B2 / Beam B2B
Limit States
Block Shear Rupture Bolt Bearing Bolt Shear Flexural Yielding Local Web Yielding Shear Rupture Shear Yielding Weld Strength
N
North Elevation
West Elevation
Notes
• • • • • • Girder B2 supports Beam B2B by a single-plate connection. The top flange of the supported beam is coped to eliminate the interference of girder flange. The weld size should be limited to three-quarters the thickness of the single plate to ensure that weld strength is not the controlling element in the connection.
4-18 • Connections Teaching Toolkit
. The plate is shop welded to the supporting girder and field bolted to the supported beam. Erection is simplified as the beam can be swung into place.

For a standard all-bolted single-angle connection. Welds on the supporting side should be placed along the toe and bottom edge of the angle. The theoretical location of the pin (assumed most flexible part of the connection) will depend on the support and tee chosen. The tee has been shop welded to the girder and field bolted to the beam. there is typically one bolt line on both plies with all the bolts in single shear. welding across the entire top edge on the supported side should be avoided since it would inhibit the flexibility of the connection. then eccentricity should be considered on the in-plane angle leg. A limited amount of rolling fillet encroachment is permitted depending on the size of the rolling fillet of the WT section. which requires a setback distance sufficient enough so as not to interfere with the rolling fillet.Figure 4-31. Tees with thick flanges may provide for rotational flexibility through stem behavior similar to that of a shear tab. like a doubleangle. Eccentricity should always be considered on the outstanding angle leg. Beams B4A and B4B demonstrate the use of single-angle connections on the steel sculpture. The single-angle for Beam B4A is shop welded to the girder and field bolted to the beam. which represent typically lightly loaded members used for infill steel framing.
Connections Teaching Toolkit • 4-19
. Properly sized weld returns should be provided at the top edge of the angle. the strength based on bolt shear alone is the same on either ply of the single-angle. Shear Connection: Single plate Girder B2 / Beam B2B
Thus. Tees with thicker flanges may provide for rotational flexibility through flange behavior similar to that of an end plate or double angle connection. Both the stem and the flange may be either bolted or welded to the appropriate members. Thus.
TEE SHEAR CONNECTION The tee shear connection is fabricated from a WT section with the stem connected to the web of the supported member and the flange attached to the supporting member. Shear Connection: Single plate Girder B2 / Beam B2B
Figure 4-32. The supported members in each of these connections are channel shapes. The AISC Manual provides suitable guidance for all cases. while Beam B4B has the single-angle field bolted to the girder and shop welded to the channel. the strength based on bolt shear alone is the same on either ply of the single-angle. If two or more lines of bolts are used on the web of the supported beam. the rotational flexibility of the single-angle connection is achieved primarily through the deformation of the outstanding angle leg. The required beam setback for a shear tee connection is greater than that of other connections. The AISC Manual gives guidance for proper design in this regard. Like a double-angle connection. The tee has a rolling fillet on each side at the junction of the flange and the stem. Eccentricity should also be considered on a welded angle leg. Beam B1A shows a tee shear connection.

The supported beam is a channel (C) shape. welding across the entire top edge should be avoided since it would inhibit the flexibility of the connection. Erection is simplified as the beam can be swung into place. Welds on the supporting member should be placed along the toe and optionally along the bottom edge of the angle. Channels have tapered flanges similar to American Standard (S) shapes.
4-20 • Connections Teaching Toolkit
.Figure 4-33 Shear Connection: Welded-Bolted Single-Angle
Girder B4 / Beam B4A
Limit States
Bolt Shear Bolt Bearing Block Shear Rupture Shear Yielding Shear Rupture Weld Strength
N
North Elevation
West Elevation
Notes
• • • • • • • Girder B4 supports Beam B4A by a welded-bolted single-angle connection. Properly sized weld returns should be provided at the top edge of the angle. Single-angle connections tend to have lower load capacities then double-angle connections. In-plane and out-of-plane eccentricity should be considered. This single-angle is field bolted to the supported beam and shop welded to the supporting girder. This is a one sided connection.

Welds on the supported side are placed along the toe of each angle and optionally along the top or bottom edges of both angles. This is a one sided connection.
Connections Teaching Toolkit • 4-21
. In-plane and out-of-plane eccentricity should be considered. Single-angle connections tend to have lower load capacities then double-angle connections. The single-angle is shop welded to the supported beam and field bolted to the supporting girder. The supported beam is a channel (C) shape. Channels have tapered flanges similar to American Standard (S) shapes. Erection is simplified as the beam can be swung into place.Figure 4-34 Figure 4-36 Shear Connection: Bolted-Welded Single-Angle Shear Connection: Bolted-Welded Single-Angle
Girder B4 / Beam B4B Girder B4 / Beam B4B
Limit States
Block Shear Rupture Bolt Bearing Bolt Shear Shear Rupture Shear Yielding Weld Strength
N
South Elevation
East Elevation
Notes
• • • • • • • Girder B4 supports Beam B4B by a bolted-welded single-angle connection.

To ensure adequate connection flexibility the welds connecting the tee flange to the supporting member and the thickness of the tee stem are subject to specific size limitations. eccentricity and tee stem flexure must be considered. This is a one-sided connection. Due to the extended setback. welding across the entire top edge should be avoided since it would inhibit the flexibility of the connection.Figure 4-41 Figure 4-39 Shear Connection: Welded-Bolted Tee Shear Connection: Welded-Bolted Tee Girder B1 / Beam B1A
Girder B1 / Beam B1A
Limit States
Block Shear Rupture Bolt Bearing Bolt Shear Flexural Rupture Shear Rupture Shear Yielding Weld Strength
N
West Elevation
North Elevation
Notes
• • • • • Girder B1 supports Beam B1A by a welded-bolted shear tee connection. Welds on the supporting member should be placed along the toe and optionally along the bottom edge of the angle. Erection is simplified as the beam can be swung into place.
•
• •
Connections Teaching Toolkit • 4-23
. This is considered a flexible support condition since the support of this connection is the web of the girder. Setback of the supported beam must extend beyond the k distance of the tee flange. The tee is shop welded to the supporting girder and field bolted to the supported beam. Properly sized weld returns should be provided at the top edge of the angle.

.

FR connections are idealized as having full fixity between members. Web doubler plates are steel plates that are fabricated to increase the overall thickness of the web of a section. the plates should be sized wide enough to fill the space within the column flanges. but narrowing outside the column to allow downhand welding. The flange-plates for Girder B2 are bolted to the top and bottom flanges of the beam. If the beam frames into the web of a column. then the plates are designed and detailed such that flange plate welding can be performed in the flat position. no relative rotation) and there is full transfer of the moments. If the flange-plates are welded to the flanges of the supporting member. Partially Restrained (PR) connections assume that there will be some relative rotational movement that occurs between intersecting members. providing adequate clearance. if the connection is made to the web of a column. This arrangement makes it easier to erect. There are several types of flangeplated connections. Moment connections also normally include a simple shear connection at the web of the supported member to carry the shear component of the beam reaction. a heavier column section or a higher strength column may be substituted. Infinite rigidity can never be realistically attained. extending plates past the column flanges). so it may be more economical to select a heavier column section or one with higher yield strength. though there will still be transfer of the moments. Most moment connections are made from the supported beam to either the flange or the web of column members (called beam-to-column connections). Thus. In some instances the column section may have insufficient local strength at the location of these concentrated forces. Both types of components (transverse stiffeners and web doubler plates) are welded to the section to enhance the stiffness. which is usually neglected. Hence. Any load eccentricity considerations in the shear connection as part of a moment connection may be ignored as it is carried by the moment connection. or transverse column stiffeners and/or web doubler plates may be installed. the connection elements may be extended so that field welds and/or bolts can be located outside of the column flanges for easier erectability. To transfer the tension and compression forces carried by the flanges. Beam splices to transfer moments are also common. In such circumstances. The use of these components will increase fabrication costs. respectively. Transverse stiffeners are plates fabricated to fit between the flanges of the column at the point(s) of concentrated loading (tension or compression). In this case the top plate will likely be wider than the top flange of the supported beam. Shims are provided to fill any of the resulting gaps. The flanges of the supported member may be either bolted or welded to the plates. This can be accomplished by using a flange-plate that is slightly narrower than the beam flange on top and a flangeplate that is slightly wider than the beam flange on the bottom. As mentioned above. Regardless of the bolting or welding arrangements. Columns in beam-to-column connections are subjected to concentrated forces from the flanges of the supported member. A Fully Restrained (FR) connection assumes the measured angles between intersecting members are maintained (i. Moment connections (or continuous or rigid-frame connections) are assumed to have little or no relative rotation between the supporting member and the supported members. the supported side attachment should provide enough space to accommodate bolting or welding access (i.e. This arrangement permits flat-position (down-hand) welding. the flange-plates
Connections Teaching Toolkit • 5-1
. the flanges of the supported member are attached to either a connection element or directly to the supporting member. to accommodate the flat welding position of flange plates attached to column webs.CHAPTER 5 Moment Connections
Moment connections transfer the moment carried by the flanges of the supported beam to the supporting member. Flangeplates are usually shop attached to the column and field attached to the flanges of the supported member. If a moment connection is made to the web of a column. Flange-plates are usually positioned slightly wider apart than the depth of the supporting member if they are to be bolted to the flanges of the supported member.e. continuity between the supported beam flanges and the supporting member must be realized. Girders B2 and B4 are bolted and welded flange plate connections to the web of Column C1. The flange-plates are fillet or groove welded to the supports. therefore. See the AISC Manual for discussion of corner clips and plate configurations when attaching to column webs. FLANGE-PLATED CONNECTIONS (BEAM-TO-COLUMN) Flange-plated connections are made with top and bottom flange-plates that connect the flanges of the supported beam to the supporting column. even fully restrained moment connections do possess some minimal amount of rotational flexibility. the top flange plate should be blocked to make an easier joint for welding to the supported member.

• • • •
5-2 • Connections Teaching Toolkit
. These flange-plates are shop welded to the supporting column and field bolted to the supported girder. The moment connection is made to the web of Column C1. The effect of eccentricity in the shear connection is neglected. For all FR and PR column connections. The flange-plates are cut to fill the space between the column flanges. column stiffening must be investigated to ensure that the connection flange forces do not exceed applicable limit states.Figure 5-1 Moment Connection: Bolted Flange-Plates
Column C1 / Girder B2
Limit States
Block Shear Rupture Bolt Bearing Bolt Shear Plate Buckling Tension Rupture Tension Yielding Weld Strength
N
South Elevation
West
Elevation
Notes
• • • • Column C2 supports Girder B2 by bolted flange-plates. The corners of the flange-plate are clipped to eliminate the possibility of creating a stress concentration at the re-entrant corner of the web-flange junction. The plates attached to the flanges of the girder are for transfer of the moment forces. No weld is provided at these locations. The plate attached to the web of the girder is for transfer of the shear force.

The moment connection is made to the web of Column C1. the area of attachment must be free of any coatings (i. The plate attached to the web of the girder is for transfer of the shear force. The flange-plates are shop welded to the supporting column and field welded to the supported girder. column stiffening must be investigated to ensure that the connection flange forces do not exceed applicable limit states.e. For all FR and PR column connections.Figure 5-6 Figure 5-4 Moment Connection: Welded Flange-Plates MomentC1 / Girder B4 Welded Flange-Plates Column Connection:
Column C1 / Girder B4
Limit States
Bolt Bearing Bolt Shear Plate Buckling Tension Rupture Tension Yielding Weld Strength
N
South Elevation
East
Elevation
Notes
• • • • • • • • Column C1 supports Girder B4 by welded flange-plates. When connection elements are field welded to members.e. oil or grease) The plates attached to the flanges of the girder are for transfer of the moment forces. The effect of eccentricity in the shear connection is neglected. paint) or lubricants (i.
5-4 • Connections Teaching Toolkit
. The flange-plates are cut to fill the space between the column flanges.

The beam may be fabricated short to
Figure 5-7. The corners of the plates have been clipped to accommodate the rolling fillets of the supporting column and separate the welds. single-angle. Both girders would normally be specified short and the connection elements extended so that all welds and bolts were located outside the column flanges for easier erectability. Girder B1 is directly welded to the flange of Column C1. Once the joint is completed. the runoff tabs are removed. fabrication. extended end-plate connections require close accommodation of mill. Both connections are attached to the web of the column.are positioned to be slightly wider apart than the depth of Girder B2 and a shim has been provided to fill the gap. Fillet welds.e. The groove welds connecting the beam to the column flanges can then be made in the flat welding position. The plates are shaped such that they fill the entire space between the flanges. Moment Connection: Directly welded flanges. A shear tab transfers the shear load to the column. but the backing bars have been left in place after welding. in practice this might prove to be a difficult connection to make in the field. Backing bars and weld runoff tabs are added to the flanges. Column C1 / Girder B1
Connections Teaching Toolkit • 5-5
. and erection tolerances and is not often used. Furthermore. Extra bolts may be placed in the plate. EXTENDED END-PLATE CONNECTIONS Extended end-plates are similar in appearance and orientation to shear end-plates. these bolts serve primarily to carry shear forces. End-plate connections are classified based on the number of bolts used at the tension flange. The bolts in tension should be arranged in a symmetrical pattern with half above and half below the tension flange. however completeor partial-joint-penetration welds may be used if the fillet size is excessively large. Like their shear counterparts. or partial-joint-penetration groove welds may be used if suitable for the required force transfer. the bolts at the compression flange should be placed between the flanges of the supported beam whenever possible to reduce the required plate length. and erection tolerances. On the steel sculpture. The shear force may be transferred by either the addition of a standard shear connection (i. shear tab. fabrication. Although the shear connection (shear tab) has not been extended (bolting of this element takes place inside the flanges of the column). DIRECTLY WELDED FLANGE CONNECTIONS Directly welded moment connections are typically made with complete-joint-penetration groove welds that directly connect the top and bottom flanges of the supported beam to a supporting column.) or by directly welding the supported beam web to the column flange. The plate is usually fillet welded to the flanges and web of the supported beam. Moment Connection: Directly welded flanges. Groove welds for directly welded flange connections require significant joint preparation. Weld access holes are cut in the web at the intersection of the flanges of the supported beam. The runoff tabs have been removed. The primary physical difference is that the plate is longer than the depth of the supported beam as it must be attached to both the web and the flanges of the supported beam. such as four-bolt unstiffened and eight-bolt stiffened. however it is sometimes permissible to leave the backing bars in place. Direct welding of the web requires very
close accommodation of mill. near the neutral axis of the beam to ensure proper fit-up with the column and assist the compression flange bolts in shear transfer. The plate is then bolted with highstrength bolts to the supporting member. At least two bolts should be used at the compression flange. Also note that the end of the beam was left unpainted to accommodate the welding of the joint. etc. Column C1 / Girder B1
Figure 5-8. It is advised to extend the shear tab.

column stiffening must be investigated. the area of attachment must be free of any coatings (i. A transverse stiffener is attached between the flanges of the support column.Figure 5-9 Figure 5-7 Moment Connection: Directly Welded Flanges MomentC1 / Girder B1 Directly Welded Flanges Column Connection:
Column C1 / Girder B1
Limit States
Bolt Bearing Bolt Shear Compression Buckling of Web Local Flange Bending Local Web yielding Weld Strength
N
West Elevation
South Elevation
Notes
• • Column C1 supports Girder B1 by directly welded flanges. The effects of eccentricity in the shear connection are neglected. The plate attached to the web of the girder is designed for shear transfer.e. Weld access holes are cut in the supported girder to accommodate welding in the flat position and to relieve thermal stresses. When connection elements are field welded to members. paint) or lubricants (i. The plate is aligned to receive the concentrated force (tension or compression) from the girder flange.
• • • • •
5-6 • Connections Teaching Toolkit
. For all FR and PR Column Connections. oil or grease) For all FR and PR Column Connections. column stiffening should be investigated to ensure that the connection flange forces do not exceed applicable limit states.e.

Girder B3 has an extended end-plate connection to Column C1 of the steel sculpture. weld access holes and backing bars may be required. The connection is a four-bolt unstiffened connection with four bolts in two rows at the top flange. The transverse stiffener is also part of the connection. This arrangement is for illustration purposes only. girders of identical cross-sections. Flanges of the two members can be directly welded to one another by a completejoint-penetration or partial-joint-penetration groove (butt) weld. MOMENT SPLICE CONNECTIONS A moment splice connection is designed to transfer flange forces across two beams or two girders that are connected
end to end to make up one longer member. Backing bars and runoff tabs.
Figure 5-12. subject to fatigue loading. Moment splices can be fashioned in a similar manner to any of the three beam-to-column moment connections previously discussed. Girder B3 / Girder B3
Figure 5-11. Girder B3 / Girder B3
Connections Teaching Toolkit • 5-7
. Moment Connection: All-bolted moment splice.accommodate field tolerances with shims furnished to fill any resulting gaps.
Figure 5-13. Girder B3 is in fact two. Flange plates can be bolted or welded on the top or bottom of both flanges on both members to transfer flange forces. Column C1 / Girder B3. spliced together with a flange-plated connection. through the column section and into Girder B1 on the south side. Extended end-plates can be used in a back-to-back arrangement at the ends of the beams to form a moment splice. Column C1 / Girder B3. in practice transverse stiffeners would be provided on both sides of the column web. There is only one such continuity plate on the steel sculpture. will need to be removed. The plate is welded between the flanges of the column section and aligned vertically with the top flanges of Girders B3 and B4. Moment Connection: Extended end-plate. Moment Connection: Extended end-plate. If the flanges are directly welded. The plate provides continuity transfer of the moment force from Girder B3 on the north side. Plates are bolted to the top of the top flanges and to the bottom of the
Figure 5-10. a shear connection (shear splice) is typically provided at the web to handle the shear force component. Like other moment connections. Moment Connection: All-bolted moment splice.

Figure 5-14 Figure 5-10 Moment Connection: Extended end-plate MomentC1 / Girder B3 Extended End-Plate Column Connection:
Column C1 / Girder B3
Limit States
Bolt Shear Bolt Tension Compression Buckling of Web Local Flange Bending Local Web yielding Shear Rupture Shear Yielding Weld Strength
N
West Elevation
North Elevation
Notes
• • Column C1 supports Girder B3 by a four-bolt unstiffened extended end-plate. only A36 grade steel should be used for the extended endplate as outlined in Volume II of the AISC-LRFD Manual of Steel Construction. A transverse stiffener is attached between the flanges of the support column. If bolting is based on bearing. Extended end-plates may only be used in statically loaded applications. the bolts may be designed for shear only. the bolts must be designed for shear-tension interaction. For all FR and PR Column Connections. Extended end-plates are classified based on the number of bolts at the tension flange and may be used with or without stiffeners. If bolting is based on slip-critical conditions. Based on current research.
• • • • •
5-8 • Connections Teaching Toolkit
. Extended end-plate connections require tight fabrication and erection tolerances. The plate is aligned to receive the concentrated force (tension or compression) from the girder flange. column stiffening must be investigated to ensure that the connection flange forces do not exceed applicable limit states.

then the bolts are in double shear and a more compact moment splice may result. The plate is bolted on both sides and transfers the shear force between webs of the girders.bottom flanges. If plates are used on both sides of each flange. The web plate is a shear splice.
5-10 • Connections Teaching Toolkit
.

COLUMN SPLICE Column splices are used when it is either economical to change column sizes or the height of the structure exceeds the available column length. When the column connection is to a base plate. then shims or filler plates must be used to fill any gaps. Column Connection: Column splice Column C1 / Column C2
Figure 6-2. In most column splices. which may be required at floor edges or openings and to ease erection. The webs of the columns should be attached by welding or by installing plates. Flange-plated splices involve attaching plates (by bolting or welding) to the flanges of the upper and lower shafts. The plates may be either bolted or welded to the upper or lower shaft. Column C1 (the lower shaft) is spliced to Column C2 (the upper shaft) by direct welding the flanges on the north side and using a welded-bolted flange plate on the south side. the splice should be sufficient to hold all parts securely in place. or directly welding of flanges may effectively splice columns. If the shear force is large. it is necessary that a suitable bearing area be provided to prevent crushing of the concrete foundation. Columns may also be spliced by directly welding the flanges of the upper and lower shafts. This would never be done in prac-
Figure 6-1. the purpose of column connections is to transfer the loads to either a supporting member or to the foundation of the structure. each of these members needs to be checked locally. If the gap is between 1/16 and ¼ in. Butt plates are used between the ends of the upper and lower shafts of the column splice. then non-tapered steel shims are required. but may also be subject to axial tension. The steel sculpture uses one joint to illustrate two different column splices. The upper and lower shafts of the column do not necessarily need to be in full bearing contact with one another. Column Connection: Column splice Column C1 / Column C2
Connections Teaching Toolkit • 6-1
. Column splices must also be designed to resist the tension forces that may develop due to uplift loads. When the force on any single column is small. which is a common occurrence. the bearing area between the columns will be sufficient to transfer the compression load. A gap up to 1/16 in. Regardless of the controlling load condition. Flange plates.CHAPTER 6 Column Connections
Columns are primarily loaded in compression. shear. is permitted without the need for repair or shimming. the friction on the contact bearing area and/or the flange plates may be sufficient to resist these forces. the column splice connection must be designed to resist these forces and hold all parts securely in place. and moment. lateral (shear) forces are typically distributed among several columns. When two columns being spliced are of different sizes but of the same nominal depth. Therefore. Butt plates are convenient when the nominal depths of the upper and lower shafts are significantly different. Column splices at perimeter locations should preferably be located four feet above a finished floor to accommodate attachment of safety cables. In addition. Engineering evaluation should be performed on gaps larger than ¼ in. When a column is used to transfer loads between a supported member and a supporting member. butt plates. Stiffeners may be required to prevent local yielding or buckling from the compression forces being transferred.

This arrangement is for illustration only. The north side stiffener is cut short and a gap is provided between the bottom edge of the stiffener and the bottom flange of the girder. The base plate for the main column of the steel sculpture is 1ft 4 in. fillet welds on each side of the plates. Typically column shapes of the same nominal depth have equal distances between the inner faces. the field bolted part of the upper splice is furnished with shims to fill the resulting gap. The anchor rods extend up through both the base plate and upper plate. the AISC Manual does provide the designer with procedures for base plate design. The end of the flange on the north side of the upper shaft (side of the directly welded flanges) has been beveled to accommodate a bevel groove weld. These plates are attached to the column flange using 3/8-in. When the column is in compression. fillet weld all around the column section. then the base plate connection becomes active. The north side of the base plate has a ¾ in. 4¼-in. however. thus reducing the possibility of buckling of the plate stiffeners. but the bottom shaft is a W12×170 while the upper shaft is a W12×106. The stiffeners improve the web buckling performance of the girder.tice. The legs of the triangular stiffener have been welded to the column flange and to the base plate using a 3/8-in. Again. the column is loaded in tension and/or shear. The base plate size is a function of the compression load and the connection to the base plate is a function of the shear and/or tension loads. while the flange and web thickness vary with respect to the nominal weight per foot of the section. wide and 1½ in. The base plate attachment on the steel sculpture shows very different connection geometry between the north and the south sides. or additional elements (i. Each of the web stiffeners is essentially the same. If. in practice only one stiffener configuration would be used. the difference lies in that south side web stiffener extends completely from the top flange to the bottom flange of Girder B4. The steel sculpture connection is for illustrative purposes. On the south side. Two different web stiffeners have been welded on each side of the web of Girder B4. Additionally a horizontal plate is attached across the top edges of the plate stiffeners by a 3/8-inch fillet weld. There is one each anchor rod between each pair of vertical plates. angles) can be connected to the column that facilitate attachment of the base plate The AISC-LRFD Specification for Structural Steel Buildings does not specify a particular method for the design of base plates. The steel sculpture also illustrates a base plate connection for a bracing strut. it bears directly on the material below. The plates are bolted to the top and bottom flanges of Girders B4 and B8. a flange plate is shop welded to the lower shaft and field bolted to the upper shaft. The compression load determines the size of the base plate. by 8-in. respectively. 4-in. The column is attached to the plate with a ½ in. Plates have been welded to each end of the pipe column. These gaps avoid having the stiffeners bear directly on plate. the splice would either have entirely welded flanges or use flange plates on both sides. 11in. It is secured to the concrete foundation with six 1¼-in. Both shafts of the column are of the same nominal depth (W12 series). Since the outer faces of the shafts are not equal. Base plates usually anchor columns to a concrete foundation by anchor rods. The gap avoids having the stiffener bear directly on the bottom flange and allows for less restrictive fabrication tolerances. The actual connection of the base plate is effectively passive when there is only an axial compression load. fillet weld. However. In addition. is supported by Girder B4 and supports Girder B8 above. BASE PLATES Column base plates are used to provide a sufficient bearing area on the material below in order that the forces in a column are properly transferred to the foundation. The three vertical plates should be placed as close together as possible and washers under the nuts of the anchor rods are used to minimize any bending of the upper plate. The base plate can be attached to the column either by direct welding of the column to the plate. long (each leg) triangular stiffener. thick. This triangular stiffener serves stiffen the base plate in cases where moment must be transferred. This upper plate has two bolt holes aligned with the anchor rod holes in the base plate.
Connections Teaching Toolkit • 6-3
.
The south side of the base plate has a series of three. In practice only one of the methods would be used on both sides stiffen and attach the column to the base plate. long. The pipe column.e. A gap is provided between the top of the base plate and the bottom edge of the stiffeners. diameter anchor rods with leveling nuts. a plate welded to the lower shaft and bolted to the upper shaft has been included for fit-up and erection. The base plates of bracing struts may be bolted or welded to other steel members. by ¾-in. thick. thick vertical plate stiffeners. Column C3.

This design uses vertical plate stiffeners with a welded top angle. SOUTH FACE: The south side attachment of the base plate is a moment connection.Figure 6-10 Figure 6-4 Column Connection: Base Plate Column Connection: Base Plate Foundation / Column C1
Foundation / Column C1
Limit States
Bolt Bearing Bolt Shear Bolt Tension Flexural Yielding Weld Strength
N
South Elevation
North Elevation
East Elevation
Notes
• • The column base plate provides suitable bearing area to prevent crushing of the concrete foundation. NORTH FACE: The north side attachment of the base plate is a moment connection. In practice. This particular layout is for illustration only. This gap avoids having to fit the stiffener to bear directly against the base-plate. the primary purpose is to provide additional material to increase the weld length and thus the shear strength of the base plate. The top angle provides a bearing surface for the anchor rods and a means to level the column. one form of stiffening or the other would be utilized on both flanges of the column. Although the triangular stiffener tends to reduce bending. The base plate on the steel sculpture has two different arrangements on one connection.
Connections Teaching Toolkit • 6-5
. This design uses a single triangular plate stiffener welded between the top of the base plate and the southern face of the column flange. There is a small gap between the bottom edge of the stiffeners and the base plate.

The pipe column acts as a compression/tension brace for Girder B8. Girder B8 is cantilevered and simply supported at the column. The north side stiffener is cut short and a gap is provided between the bottom edge of the stiffener and the bottom flange of the girder. in practice only one stiffener configuration would be used. lateral) and/or tension (i.Figure 6-11 Figure 6-9 Column Connection: Base Plate (Bracing Column) Column Connection: /Base Plate (Bracing Column) Girder B4 / Column C3 Girder B8
Girder B4 / Column C3 / Girder B8
Limit States
Bolt Bearing Bolt Shear Bolt Tension Prying Action Shear Rupture Shear Yielding Weld Strength
N
North Elevation (Top)
North Elevation (Bottom)
East Elevation (Bottom)
Notes
• • • The bracing column is bolted to the top flange of Girder B4 and the bottom flange of Girder B8. the difference lies in that south side web stiffener extends completely from the top flange to the bottom flange of Girder B4. however the connections of the pipe column should be designed for any shear (i. The brace acts primarily in compression.e. uplift) loads. Each of the web stiffeners is essentially the same. Acting in compression. The plate is shop welded to the supporting pipe column and bolted to the supported girder. To manage the localized load from the pipe column.
• •
6-6 • Connections Teaching Toolkit
. The gap avoids having the stiffener bear directly on the bottom flange and allows for less restrictive fabrication tolerances. Girder B6 would be unstable without the pipe column to transfer the load to rigidly supported Girder B4 below. the pipe column delivers a concentrated load to the web of the lower girder (Girder B4). two different web stiffeners have been added to Girder B4.e. This arrangement is for illustration only.

Column C2 / Girder B6
Figure 7-2. plate & rod. Stiffeners may be required to handle the concentrated forces often associated with axially loaded members. Column C2 / Girder B6. Most braces are axially loaded compression or tension members. Misc.
Figure 7-4. Misc. The clevis transfers tension from the threaded rod into double shear on the pin. Connection: Clevis. These connections might be specified for specific types of members such as roof joists or truss members. There are many sizes of clevises available to take an assortment of different rod and pin sizes. Misc. They may also include connections with unusual framing geometry such as skewed or canted connections. Connection: Clevis. Connection: Clevis.
Connections Teaching Toolkit • 7-1
. Connection: Clevis. CLEVISES Bracing members are typically used to add stiffness and/or stability to a structure. Column C2 / Girder B6. Misc. The advantage is that the brace member may be slender (such as a cable or rod). The clevises are
Figure 7-1. Clevises are mechanical fixtures that are designed to transfer load from a threaded rod to a transverse pin. Substantial material savings in both the brace member and the connection may be possible if the bracing is designed as a tension only member. Rarely will a bracing member need to transfer shear or flexure. The pin is secured through a hole in a plate that is joined to the appropriate steel member. plate & rod. plate & rod.CHAPTER 7 Miscellaneous Connections
Miscellaneous connections are attachments that cannot be characterized by one of the connection categories previously discussed. plate & rod Column C2 / Girder B6
Figure 7-3.

Connection: Clevis. Without the tension rod attached to the end. Connection: B6 Column C2 / Girder Clevis.Figure 7-5 Figure 7-1 Misc. Plate & Rod Misc. Girder B6 would be unstable.
7-2 • Connections Teaching Toolkit
. The pin that attaches the clevis to the plate is in double shear. The rod acts as a support for the girder. Strengths (and dimensions and weights) for different size clevises are given in the Manual of Steel Construction. The girder is simply supported at the column. Plate & Rod
Column C2 / Girder B6
Limit States
Pin Bearing Pin Shear Tension Rupture Tension Yielding Weld Strength
N
South Elevation
South Elevation
West Elevation
Notes
• • • • • Column C2 supports Girder B6 with a #3 clevis and 13/8 inch diameter rod. A tapered washer and is used in conjunction with a nut to attach the rod to the column web.

The opposite end of the rod passes through a slotted hole in the column web and is anchored with a tapered (or hillside) washer and a nut. Connection: Bolted-welded bent-plate. Misc. Girder B5 / Beam B5A
Figure 7-9. the cantilevered girder would collapse. A single bent plate at each end attaches the channel brace that obliquely spans between the ends of Girders B4 and B5.
SKEWED CONNECTION (BENT-PLATE) Skewed connections result from members that do not frame together in an orthogonal fashion. Girder B5 / Beam B5A
Figure 7-8. Misc. The clevis uses a 1¾-in. long threaded end at the lower end of the rod. Misc. a pair of plates may be bent. Extended gages may be necessary for suitable entering and tightening clearances. pin that is secured through a plate that is welded to the top flange of the girder. The tension rod that supports propped cantilever Girder B6 is probably the most obvious bracing member on the steel sculpture. The seat connection is assumed to provide no rotational restraint. Any eccentricities that result from skew should be duly considered.
Figure 7-6. Skewed connections may be made by a bent plate. The tension brace supports the girder with a #3 clevis that is screwed on the 4 in. The design strength of a clevis is based on the size of the clevis. Misc. or if more strength is required. The design of a bent plate or skewed double-plate is analogous to similar shear connections. The plates are field bolted to the girder and shop welded to the channel. Connection: Bolted-welded bent-plate. The skew angle is about 45 degrees. The plate or double-plates may be bolted or welded on the supporting side or the supported side.classified based on a clevis number that represents the outer diameter of the eye. thus without the tension brace. Connection: Welded joist Girder B5 / Joists B9A & B9B
Figure 7-7. Girder B6 requires a tension brace because the connection that attaches the girder to the column is a seat connection. Connection: Welded joist. Girder B5 / Joists B9A & B9B
Connections Teaching Toolkit • 7-3
.

The purlin has been bolted to the top chord of the roof truss. On the steel sculpture Truss B7 is framed into the north face of Column C2 using gusset plates. The Steel Joist Institute (SJI) and joist manufacturers provide connection guidelines for these members. Four open web steel joists welded to Girder B5 illustrate the attachment of these members. When several truss members frame together. the upper flange should be installed facing up slope. the studs become embedded in the concrete. Cutting. Connection guidelines for cold-formed members can be found in the American Iron and Steel Institute (AISI) “Cold-Formed Steel Design Manual. Z purlins have point symmetry and have a tendency to rollover on inclined slopes (such as this roof truss).OPEN WEB STEEL JOIST Open web steel joists are pre-manufactured standardized structural members. Girder B1 / Shear Studs
Figure 7-14. Misc. A group of eight shear studs have been attached to Girder B1 on the steel sculpture. COLD-FORMED ROOF PURLIN In metal building systems. Gusset plates must be sized for buckling under compression. Girder B1 / Shear Studs
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. compression.
Figure 7-13. Misc Connections: Shear studs.” The Z shaped cold-formed steel roof purlin B9 is attached to Truss B7 on the steel sculpture. Members are loaded either in tension. then the moving load causes stress reversal in the members and slip-critical joints must be used. tension yielding. the joist connection is typically subject to bearing and tension (uplift) loadings. Truss B7 / Purlin B9. When used for roof framing. and bending thin sheets of steel form cold-formed steel members. If the connections are bolted and the truss is for a bridge application. Connection: Z Purlin. tension rupture. The studs are resistance welded to the top flange of the beam through the metal deck (note: no metal decking is included in the Steel Sculpture). TRUSS CONNECTIONS Trusses are typically used as a roof framing system or in bridge applications. Misc Connections: Shear studs. rolling. SHEAR STUD CONNECTORS Shear stud connectors are used in composite construction to transfer horizontal shear forces between a steel beam and a concrete slab. block shear rupture and Whitmore section buckling and yielding. or bending and may be welded together. the line of action for the force should preferably meet at a common work point. Gusset plates provide the extra area necessary for welding or bolting.
Figure 7-12. When a concrete slab is poured over the metal deck and beam. roof purlins are often coldformed steel members. To prevent the Z purlins from rolling over. or bolted or welded together using gusset plates.

which need to be considered. design requirements thereby making them less tolerant to changes in design parameters. many of which are based on relatively complex behavior.
Connections Teaching Toolkit • 8-1
. connections have many limit states. sometimes conflicting. Connection design requires satisfying several. Slight adjustments in the design parameters of connections may drastically affect the strength and/or performance of the connections. In general.CHAPTER 8 Closing Remarks
The importance of proper connection design cannot be overstated.

• Output is registered in the two tables (Summary 1 and Summary 2 at the end of the worksheet. the middle column represents the connection element and the last column represents the supported member. each connection module has access to each library. The origin is defined as one (ORIGIN=1) in all worksheets and for all functions. These regions are typically unnecessary for expansion and viewing. double click on the arrow near the left margin. Libraries are simply worksheets that contain nothing but globally defined functions or definitions.mcd This library lists the definitions used in the connection modules. At the end of the worksheet are two output tables summarizing the analysis results. • Expand the collapsed yellow areas for additional. The idea of independent plies is extended even further by making use of an extensive subscripting convention. Libraries are lists of functions and/or definitions that are referenced by the connection modules. variables. and areas. These libraries are characterized by the purpose of the functions that they contain. the heading will be subdued with a gray font and “**Not applicable to this connection**” will be written below. There are essentially two main types of worksheets: libraries and connection modules. Functions. Grey areas indicate regions of internal calculations that are either the extensive connection property calculations or sorting/organizational in nature. the joint type and other properties. Connection Modules These are the MathCAD® worksheets that the user will work with to perform a particular connection analysis. Text-based input parameters are assigned integer values so they will work properly inside of functions and programs. FUNCTION INVESTIGATION • To see how particular functions are defined. input-output part of the software. Tee.) The placement of the headings within the worksheets has some significance. There are several libraries available to each module.CONNECTION ANALYSIS • Open the preferred connection module. most users will find it helpful to understand the basic structure of how the software application works. Use caution when modifying and saving worksheets. In addition. Each ply and/or member of a particular connection is organized into a “column” in the connection modules. etc. Single-angle. The HUB worksheet is in turn referenced by each connection module worksheet. For example the first column represents the supporting member. COMPARATIVE STUDIES Change any of the input values and the worksheets will automatically update the output values. the connection modules take advantage of the organizational features of MathCAD® including colors. Most descriptive text and headings are in a black Arial font. definitions. or calculations that may be of interest to the user. Connection modules are the front-side. No password is required to unlock these areas. The above mentioned connection module worksheets reference all the libraries so that the module can have access (call upon) a particular function. Most variables have subscript text describing which ply or connection side they are associated. • Input values for all input parameters (MathCAD® does not handle null values). The first output table (Summary 1) lists the limit states and their applicability or strength. HOW IT WORKS Although extensive knowledge of MathCAD® is not required. in the connection module. etc. A description of each library and an example function or definition for most libraries follows: • Definitions. the section and connection geometries. Thus. (See MathCAD® documentation for more information on areas. The columns are arranged left to right for a righthand connection. fonts. Whenever a particular property of the
connection does not apply. Areas can be recognized as either a gray or yellow colored stripe with an arrow and heading at the left margin. (The gray areas have been locked by default. The various input and output sections are arranged in the same manner from module to module. Libraries The second type of worksheet is the library. more detailed connection data. Each library is referenced by the HUB worksheet.) The yellow areas are either output. there are seven library worksheets.) The user will enter the load. To expand or collapse an area. The second table (Summary 2) lists serviceability and/or other design checks and whether the required design criteria have been met. Areas are a MathCAD® feature that allows sections of a worksheet to be collapsed and/or locked. There is one connection module for each type of shear connection (Double-angle. open the appropriate library **NOTE: There is no active worksheet protection.
Connections Teaching Toolkit • 8-3
. Currently. All text based input parameters are written in all capital letters. are in a blue Times New Roman font. Each connection module is organized in a similar fashion.

Many of these functions reproduce chart and table values found in the AISC-LRFD Manual of Steel Construction. Ply: In-plane angle leg(s). the second returns section properties for a WT shape. Ag and Fy. Vertical_Leg PL Associated Element or Ply: Element: Supporting member. For purposes of this manual the subscript position in variable definitions and explanations is indicated by “…” where “…” represents the actual subscript Subscript: Supporting Supported Beam_Web T Tee_Stem Tee_Flange A Leg1.Example: Simple integer values are assigned to variables for thread condition definition. Ply: Supported member web. or “OK” otherwise. Ply: Outstanding angle leg (seat connection). The advantage of functions is that they can be used repeatedly to perform the same operation using different argument values. The function returns the caption “Minimum factored load is 10 kips if the criteria is not met. Input The input region should be evident in the worksheets.
• User. Pu. All input parameters are essentially the same from module to module.
8-4 • Connections Teaching Toolkit
. Values are required for each variable under the Input Parameters heading.mcd The design checks library contains functions that determine if general design criteria have been met. • Section Properties. Ply: Shear tee flange. Example: Function to return the effective throat of the weld. Ply: Vertical angle leg (seat connection). Functions are essentially subroutines that have arguments passed to them. and calculates the nominal shear yielding strength. Example: Shear yielding limit state function. Example: Definition that assigns the value 0. • Phi Factors. Ply: Shear tee stem. Example: Minimum factored load function. • Miscellaneous. Element: Angle or double-angle.mcd The miscellaneous library contains those functions that do not fall neatly within one of the other libraries. SUBSCRIPTING The worksheet variables use an extensive subscripting convention to indicate which element or ply the variable is applicable. MathCAD® cannot have null values for variables. Most functions are defined in one of the previously mentioned libraries. Functions can be identified in the worksheets by the prime “ ‘ “ notation that precedes the name of every function.
FUNCTIONS. Element: Shear tee.mcd The phi factors library defines the resistance factors for different categories of limit states from the AISCLRFD Manual of Steel Construction. and does a simple check to see that the argument is greater than 10 kips. • Design Checks. INPUT. LIMITATIONS Functions Most calculations in the worksheets are done by functions. Legs1 Leg2. This function requires two arguments: Process and w. OUTPUT. The first returns section properties for a W shape. Element: Plate. These are the main functions to calculate the strength for a given limit state. based on the size of the weld and the process used.mcd The user library is a blank/empty worksheet library for that is available for user-defined functions. This is true regardless of the bolting and welding combination. This function requires only one argument. Legs2 Outstanding_Leg.mcd The section properties library contains only two functions.mcd The functions in the limit states library are from the AISC-LRFD Manual of Steel Construction.90 to the phi factor based on shear yielding. perform calculations on the arguments and then return results. Element: Supported member. • Limit States. These functions also make sure that there is no geometric interference between the connection elements given their size and position. Ply: Out-of-plane angle leg(s). This function requires two arguments.

Weld size in inches Length (Height) of vertical weld in inches Length (Width) of horizontal weld segments in inches (Both top and bottom horizontal weld segments must be the same length). Minimum load (based on AISC-LRFD Manual of Steel Construction) is 10 kips. Support condition. AISC wide flange members only (WT members available as connection element for the Shear tee connection module). column web (WEBC). for supporting and supported member. Determines whether the girder web (WEBG). or column flange (FLANGE) supports the connection. This variable takes a text-based input value. Copes must be deeper than the flange thickness. Length of cope(s) in inches Both top and bottom copes must be the same length. for supporting and supported member. Weld metal strength in ksi. This variable takes a text-based input value. Determines whether the joint is bolted (BOLTED) or welded (WELDED).
Setback
dcb
c
D_…
FEXX_… Process_…
W_…
weld_… dweld_…
Leg1_…
bweld_… Leg2_… In-plane leg (or horizontal leg for seated connection) length in inches Width of plate in inches db_… L_… t_… Length of plate in inches Thickness of connection element in
W_…
Connections Teaching Toolkit • 8-5
. Member designation. gas metal arc welding (GMAW). Value of slip coefficient between faying surfaces. Outstanding leg (or vertical leg for seated connection) length in inches
Support
y_…
dct m. flux core arc welding (FCAW). Beam setback in inches Shortest distance from face of support to the web of supported beam Fy_… Yield strength of particular member in ksi.
Connection shear loading in kips. Mean slip coefficient. Vertical alignment in inches Alignment is measured from the mid-depth of the connection element to the mid-depth of the beam or girder. This variable takes a text-based input value. Determines whether the weld is made by the shielded metal arc welding (SMAW). AISC wide flange members only (WT members available as connection element for the Shear tee connection module). Member designation. nominal weight per linear foot in pounds. Depth of top cope in inches Enter 0 for no top cope. Only gravity loads are permitted. nominal depth in inches. Copes must be deeper than the flange thickness. Bolt diameter in inches. or submerged arc welding (SAW) process. Welding process.Input Parameter: Pu
Explanation: Joint_…
inches Joint condition. Depth of bottom cope in inches Enter 0 for no bottom cope. Fu_… Ultimate strength of particular member in ksi.

or Long-slotted/load parallel (LSLP) Vertical edge distance. then resistance to slip is 0 kips. Long-slotted/load transverse (LSLT). If the connection is bearing. Weld strength for sides of the connection that are welded based on the strength of the weld or the base material. Bolt bearing limit state for sides of the connection that are bolted.ASTM_…
ASTM Bolt designation. Determines whether the bolt threads are iNcluded (N). Limit State: Slip Explanation: Slip resistance based on factored load. or Slip-critical (SC). Bolt gage in inches (gage is measured normal to direction of load). Shear Rupture Shear rupture for each applicable ply of material. This variable takes a text-based input value. for a given ply of connection element. This limit state applies to the connection element and the supported member if it is double coped. for a given ply of connection element. The first table (Summary 1) returns the connection loading and strengths of applicable limit states. Bolt Shear Bolt shear limit state for sides of the connection that are bolted. “NA” is returned. If a limit is not applicable for given the connection parameters. Bolt group thread condition.
Output Primary results (limit state strengths and design checks) are returned in two tables at the end of the connection modules. in inches. Hole_… Hole type for a given ply of material: Standard (STD).
Threads_…
required strength.
Bolt Bearing
Lev_…
Weld
Leh_…
Flexural Yielding of Beam Flexural yielding limit state for supported beams that are coped. Number of bolt rows on a given side of the connection (rows are normal to direction of load). This limit state applies to the connection element and the supported member if it is double coped. The output table only provides a listing of the applicable limit states and their respective strengths. Block Shear Rupture Block shear rupture for each applicable ply of material. in inches. This limit state applies to the connection element if it is bolted and to the supported member if it is bolted and top coped. Oversized (OVS). Bolt spacing in inches (spacing is measured parallel to direction of load). eXcluded (X).
s_…
g_…
Shear Yielding Shear yielding for each applicable ply of material. Short-slotted/load parallel (SSLP). Determines whether the bolts are A325 (325) or A490 (490). No flags or warnings are issued if the strength of a limit state is less than the
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. Horizontal edge distance.
Rows_…
Columns_…
Columns_Supporting_HF Number of bolt lines per flange of a double-angle or shear tee connection. Number of bolt lines on a given side of the connection (columns are parallel to direction of load). Short-slotted/load transverse (SSLT).

the checks included tend to represent the most common concerns and issues. Element vs. Only general design check functions are written in and thus called from the design checks worksheet library.e. etc. Column Checks that the width of the connection element is compatible with the column.
The second table (Summary 2) returns common design checks. Column Web Checks that the width of the supported beam does not exceed the “T” dimension of the column. Minimum Size of Cope(s) Checks that the cope(s) extend past the flange thickness of the supported beam.
Homogeneous Fastener Use Checks that the bolts are common to both sides of the connection for an allbolted connection (i. minimum weld size).
Connections Teaching Toolkit • 8-7
. Girder Checks that the depth of the supported beam does not exceed the “T” dimension of the girder. Web Crippling of Beam Web crippling limit state for unstiffened seat connections. Local Web Yielding of Beam Local web yielding limit state for unstiffened seat connections. Other checks are common to each shear connection (e.g.Local Web Buckling of Beam Local web buckling limit state for supported beams that are top or double coped. “Design check” is a general term that relates to the serviceability. both sides have same grade. erectability. same diameter.g. Beam Checks that the length of the connection element is compatible with the beam. Beam vs. single plate connection). There are two kinds of design checks. Element vs. Prying Action Prying action limit state for shear tee connections with a bolted flange. or connection performance issues. Checks that there is no geometric interference between the beam and the girder based on the vertical alignment of the members. Cope Length Checks that the cope is long enough to accommodate the girder flange. the general design checks for the different connection modules are not all-inclusive. If the design check is specific to a particular connection. Beam Alignment Checks that there is no geometric interference between the beam and the connection element based on the vertical alignment of the members. its function is included inside the connection module worksheet. Also. or a short caption describing the issue for non-compliance. The design checks return either an “OK” meaning all required criteria for a particular design check has been met.
Minimum Factored Load Checks whether or not the user has input a design load of at least 10 kips.) Girder Alignment Checks that there is no geometric interference between the girder and the connection element based on the vertical alignment of the members. Some checks are specific to a particular connection type (e. Design Check: Explanation:
Interference
Beam vs.

Even if a connection is all-bolted. (i. and they must be the same length. Bolt Hole Check Checks the proper use of oversized. Bolt Hole Spacing Checks for adequate bolt hole spacing. (e. Checks that oversized holes are used only in conjunction with slip-critical connections. • The unstiffened seat connections module is somewhat unique. No L shaped weld groups are permitted). The best example of this is the BOLTED/WELDED switch.e. • Only wide flange shapes for beams and girders are presently allowed. enter 70 ksi welds. Beam vs. To facilitate proper logic in the flow of the programs. Beam vs. they must be used at both the top and the bottom. With careful geometry and alignment it may be possible to encroach on the rolling fillet areas of girders. Additional. Checks that long slotted holes are used in only one ply of material. If horizontal welds are to be used on the supported side.Minimum Fillet Weld Checks that the fillet weld size satisfies the minimum size requirements. several variables are defined that act as switches and tell the programs what variables and functions to calculate and which ones to ignore. etc. Girder.e. weld size. • Some of the design checks that analyze the compatibility of certain connection member lengths and widths (i. and slotted holes. Weld Length Check Checks that the element being welded has a sufficient edge length for the specified length of weld.
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. more detailed output and/or calculations can been viewed by expanding any or all of the yellow areas. Maximum Fillet Weld Checks that the fillet weld size satisfies the maximum size requirements. The gray areas contain sorting functions or extensive internal calculations that would typically not need to be seen by the user. ¼ in. and columns. • MathCAD® does handle null values for variables (there must be a value for every variable in the worksheet). Element vs.g. Beam) check the web depth of flange width of the beam against the T dimension of the girder or column.) The text value definition BOLTED input at the JOINT variable effectively tells the worksheet to ignore any welded values and functions. Limitations Although the worksheets are versatile. Checks that the lengths of slotted holes are normal to direction of load in bearing connections. Column. It is the only shear connection with no joint at the web of the supported beam. In some circumstances these checks are conservative. some limitations do exist: • Only vertical weld lines are permitted on the supporting side of a connection. there must be values in the variables for welded properties. No provisions exist in the worksheet for interference design checks or beam copes. beams.